Different chemical strategies to aminate oxidised multi-walled carbon nanotubes for siRNA complexation and delivery.

In this work, we have investigated the preparation of amino-functionalised multi-walled carbon nanotubes (MWCNTs) as potential carriers for the delivery of siRNA. Several studies have shown promising results exploiting functionalised CNTs for the delivery of genetic material in vitro and in vivo. Our groups have previously observed that the type of surface functionalisation used to modify oxidised MWCNTs (oxMWCNTs) can lead to significant differences in nanotube cellular uptake and delivery capability. In those studies, amino-functionalised CNTs were obtained by cycloaddition reactions. Here, we focused on the direct conversion of the carboxylic groups present on oxMWCNTs into amines, and we attempted different synthetic strategies in order to directly tether the amines onto the CNTs, without extending the lateral chain. The functionalised material was characterised by X-ray photoelectron spectroscopy, Fourier transform infra-red spectroscopy and transmission electron microscopy, and the most water-dispersible CNTs were selected for siRNA complexation and cellular uptake studies. The aminated conjugates are demonstrated to be promising vectors to achieve intracellular transport of genetic information.

[1]  Maurizio Prato,et al.  Making carbon nanotubes biocompatible and biodegradable. , 2011, Chemical communications.

[2]  M. Prato,et al.  Functionalized Carbon Nanotubes in the Brain: Cellular Internalization and Neuroinflammatory Responses , 2013, PloS one.

[3]  M. Prato,et al.  Microscopic and spectroscopic characterization of paintbrush-like single-walled carbon nanotubes. , 2006, Nano letters.

[4]  Kostas Kostarelos,et al.  The long and short of carbon nanotube toxicity , 2008, Nature Biotechnology.

[5]  John Parthenios,et al.  Chemical oxidation of multiwalled carbon nanotubes , 2008 .

[6]  J. Harborth,et al.  RNAi therapeutics: an update on delivery. , 2008, Current opinion in molecular therapeutics.

[7]  Marco Orecchioni,et al.  Impact of carbon nanotubes and graphene on immune cells , 2014, Journal of Translational Medicine.

[8]  H. Dai,et al.  Carbon Nanomaterials for Biological Imaging and Nanomedicinal Therapy. , 2015, Chemical reviews.

[9]  Quan Qing,et al.  Effect of Chemical Oxidation on the Structure of Single-Walled Carbon Nanotubes , 2003 .

[10]  M. Prato,et al.  Antitumor activity and prolonged survival by carbon-nanotube-mediated therapeutic siRNA silencing in a human lung xenograft model. , 2009, Small.

[11]  Sujit Roy,et al.  Is metal necessary in the Hunsdiecker-Borodin reaction? , 1998 .

[12]  Maurizio Prato,et al.  Asbestos-like pathogenicity of long carbon nanotubes alleviated by chemical functionalization. , 2013, Angewandte Chemie.

[13]  F. Toma,et al.  Potentiometric titration as a straightforward method to assess the number of functional groups on shortened carbon nanotubes , 2010 .

[14]  Yingge Zhang,et al.  The application of carbon nanotubes in target drug delivery systems for cancer therapies , 2011, Nanoscale research letters.

[15]  H. Ali-Boucetta,et al.  Pharmacology of carbon nanotubes: toxicokinetics, excretion and tissue accumulation. , 2013, Advanced drug delivery reviews.

[16]  M. Prato,et al.  Cellular uptake of functionalized carbon nanotubes is independent of functional group and cell type. , 2007, Nature nanotechnology.

[17]  A. Dalton,et al.  Are carbon nanotubes a natural solution? Applications in biology and medicine. , 2013, ACS applied materials & interfaces.

[18]  Kostas Kostarelos,et al.  Carbon nanotubes as vectors for gene therapy: past achievements, present challenges and future goals. , 2013, Advanced drug delivery reviews.

[19]  H. Grennberg,et al.  Reproducibility and Efficiency of Carbon Nanotube End‐Group Generation and Functionalization , 2009 .

[20]  M. Prato,et al.  Functionalized carbon nanotubes for plasmid DNA gene delivery. , 2004, Angewandte Chemie.

[21]  M. Woodle,et al.  Delivering Small Interfering RNA for Novel Therapeutics , 2008, Methods in molecular biology.

[22]  M. Prato,et al.  Cancer therapy: Small 10/2009 , 2009 .

[23]  Jianfeng Zheng,et al.  A facile method to modify carbon nanotubes with nitro/amino groups , 2010 .

[24]  T. Tuschl,et al.  Duplexes of 21-nucleotide RNAs mediate RNA interference in cultured mammalian cells , 2001, Nature.

[25]  Robert Langer,et al.  A combinatorial library of lipid-like materials for delivery of RNAi therapeutics , 2008, Nature Biotechnology.

[26]  F. Toma,et al.  Degree of chemical functionalization of carbon nanotubes determines tissue distribution and excretion profile. , 2012, Angewandte Chemie.

[27]  Jerry March,et al.  Advanced Organic Chemistry: Reactions, Mechanisms, and Structure , 1977 .

[28]  Judy Lieberman,et al.  Interfering with disease: a progress report on siRNA-based therapeutics , 2007, Nature Reviews Drug Discovery.

[29]  A. Fire,et al.  Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans , 1998, Nature.

[30]  Maurizio Prato,et al.  Endowing carbon nanotubes with biological and biomedical properties by chemical modifications. , 2013, Advanced drug delivery reviews.

[31]  Araceli Rodríguez,et al.  Multiwalled Carbon Nanotubes for Liquid-Phase Oxidation. Functionalization, Characterization, and Catalytic Activity , 2006 .

[32]  Sujit Roy,et al.  Catalytic Hunsdiecker Reaction and One-Pot Catalytic Hunsdiecker–Heck Strategy: Synthesis of α,β-Unsaturated Aromatic Halides, α-(Dihalomethyl)benzenemethanols, 5-Aryl-2,4-pentadienoic acids, Dienoates and Dienamides , 2000 .

[33]  K. S. Coleman,et al.  Iodination of Single-Walled Carbon Nanotubes , 2007 .

[34]  Roberto Madeddu,et al.  Ex vivo impact of functionalized carbon nanotubes on human immune cells. , 2012, Nanomedicine.

[35]  Lucia Gemma Delogu,et al.  Functionalized carbon nanotubes as immunomodulator systems. , 2013, Biomaterials.

[36]  F. Carrasco-Marín,et al.  Changes in surface chemistry of activated carbons by wet oxidation , 2000 .

[37]  M. Itkis,et al.  Chemistry of single-walled carbon nanotubes. , 2002, Accounts of chemical research.

[38]  Bing Yan,et al.  Endosomal leakage and nuclear translocation of multiwalled carbon nanotubes: developing a model for cell uptake. , 2009, Nano letters.

[39]  Maurizio Prato,et al.  Enhanced cellular internalization and gene silencing with a series of cationic dendron‐multiwalled carbon nanotube:siRNA complexes , 2010, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[40]  E. Campbell,et al.  Covalent amino-functionalisation of single-wall carbon nanotubes , 2005 .

[41]  Craig A. Poland,et al.  Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity in a pilot study. , 2008, Nature nanotechnology.

[42]  M. Prato,et al.  Functional motor recovery from brain ischemic insult by carbon nanotube-mediated siRNA silencing , 2011, Proceedings of the National Academy of Sciences.

[43]  E. Kaiser,et al.  Color test for detection of free terminal amino groups in the solid-phase synthesis of peptides. , 1970, Analytical biochemistry.

[44]  Kostas Kostarelos Carbon nanotubes: Fibrillar pharmacology. , 2010, Nature materials.

[45]  Sujit Roy,et al.  Catalytic Hunsdiecker Reaction of α,β-Unsaturated Carboxylic Acids: How Efficient Is the Catalyst? , 2002 .

[46]  M. Prato,et al.  Ammonium and guanidinium dendron-carbon nanotubes by amidation and click chemistry and their use for siRNA delivery. , 2013, Small.

[47]  A. Hirsch Functionalization of single-walled carbon nanotubes. , 2002, Angewandte Chemie.

[48]  Frank T. Fisher,et al.  Amino-Functionalized Carbon Nanotubes for Binding to Polymers and Biological Systems , 2005, Chemistry of Materials.

[49]  N. Bottini,et al.  Conjugation of antisense oligonucleotides to PEGylated carbon nanotubes enables efficient knockdown of PTPN22 in T lymphocytes. , 2009, Bioconjugate chemistry.

[50]  S. Biniak,et al.  The characterization of activated carbons with oxygen and nitrogen surface groups , 1997 .

[51]  A. Salazar,et al.  Carboxylation treatment of multiwalled carbon nanotubes monitored by infrared and ultraviolet spectroscopies and scanning probe microscopy , 2007 .

[52]  C. Crescio,et al.  Immunomodulatory properties of carbon nanotubes are able to compensate immune function dysregulation caused by microgravity conditions. , 2014, Nanoscale.

[53]  F. Toma,et al.  Design of Cationic Multiwalled Carbon Nanotubes as Efficient siRNA Vectors for Lung Cancer Xenograft Eradication. , 2015, Bioconjugate chemistry.